The female body is an amazingly beautiful, incredibly complex and often confounding thing. If you need proof, witness these fascinating facts we’ve gathered in honor of National Women’s Health Week. We’ve rounded up 52 bits of cocktail conversation fodder, ranging from the enlightening (why are women more naturally flexible than men?) to the downright bizarre (what do breast milk and marijuana have in common?). Do we have your attention now? Good! Read on, and prepare to be amazed.

Women hear differently than men: Brain scans show that women listen with both sides of the brain while men only use one.

A woman’s uterus stretches up to 500 times its normal size during labor.

Females may be more genetically predisposed to fear insects, studies suggest. Researchers guess this trait is left over from our female hunter-gatherer ancestors, who would have needed to be wary of dangerous insects in order to protect their young.

Hormones released during pregnancy can make nipples temporarily darker.

Female humans are the only primates to have permanently rounded, plump breasts. In other mammal species and non-human primates, enlarged breasts indicate that the female is suckling her young.

Call us natural-born yogis: Compared to men, women evolved more flexible and supportive spines to accommodate the strain of pregnancy.

There is a biological reason as to why women cry more frequently than men: Women’s bodies possess 50 to 60 percent more of the hormone prolactin, which aids in the production of tears, in their bodies.

The average woman today will experience around 450 periods in her lifetime.

During pregnancy, a woman’s sense of smell and taste is dramatically heightened. Scientists predict this was an evolutionary defense to ensure that pregnant women didn’t consume any toxins that would be dangerous to the developing fetus.

A woman’s natural vaginal lubricant contains an organic compound called squalene, which is also found in sharks.

Women have more sweat glands than men, but men’s glands are more active, meaning they sweat more during a given workout.

Yes, you have an Adam’s apple, too! We think of them as being a male-only trait, but Adam’s apples are universal. Male Adam’s apples are more prominent simply because the male larynx grows differently than a woman’s to accommodate the male’s longer, thicker vocal cords.

Females are born with about 1 million eggs.

During childhood, only 300 to 500 of those initial 1 million eggs will then develop into mature eggs across a woman’s reproductive lifespan.

Some studies suggest that a woman’s pain tolerance can vary over the course of the menstrual cycle.

Sleeping on your chest can alter the shape of your breasts over time.

The ovary is about the size of an almond, whereas the human uterus is about the size of a pear.

Studies have found that women are more attractive to men during ovulation, when they are at their most fertile.

Call it an act of love: Breastfeeding releases oxytocin and prolactin, hormones that relax the mother and make her feel more nurturing toward her baby.

Because of increasing life expectancy, many women will spend up to 40 percent of their lives in the postmenopausal stage.

The uterus contains some of the strongest muscles in the female body.

Turns out that the coveted “pregnancy glow” is actually a thing: During pregnancy, the amount of blood in the body increases by 50 percent, giving cheeks a flushed appearance.

Most women have one breast that tends to be larger than the other—usually the left.

A recent study found that 48 percent of regular headache sufferers had their pain cured by orgasm. The phenomenon is largely due to the body’s release of a chemical called oxytocin during orgasm, which facilitates bonding, relaxation and positive emotional stress.

An unknown number of women are endowed with an extra cone in their eyes that enables them to perceive a whole range of colors invisible to the rest of us. These so-called tetrachromats see hues of colors for which there are no name.

Almost three-quarters of women produce more breastmilk in their right breast, with no correlation to right- or left-handedness.

Several major studies have found that human breast milk naturally contains many of the same cannabinoids found in marijuana. Believe it or not, similar to how marijuana stimulates the “munchies” in users, cannabinoids in breast milk triggers hunger and promotes growth in newborns. Without these cannabinoids, newborn children might not have the desire to eat.

Feeling blue? Research shows women’s brains may be wired differently, making them twice as likely to suffer from depression and anxiety. Women’s brains have less serotonin—a neurotransmitter that regulates mood—than men’s.

The clitoris is the only human organ that has no purpose other than to provide pleasure.

In some pregnant women, the heart enlarges due to increased blood volume placing extra pressure on the heart.

Brain scans have found that women have 10 percent more white matter in their brains, which helps connect the different parts of the brain. This might explain why women are often more adept at multi-tasking than men.

The clitoris has 8,000 nerve endings, compared to 4,000 in the penis.

On average, the normal period releases less than one cup of blood.

Women who take oral contraceptives blink 32 times more than women who don’t.

The largest cell in the human body is the female egg.

In recent years, the average bra size has swelled from a 34B to a 36D.

Women have a more sensitive sense of smell than men. In studies, women outperformed men in their ability to identify certain smells.

A woman’s brain shrinks by as much as 4 percent during pregnancy, according to a 2002 study published in the American Journal of Neuroradiology. It does not lose cells but simply changes metabolism.

An adult woman of reproductive age has fairly acidic vagina, with a PH around 3.8—comparable to that of a tomato.

It’s a common misconception that breast size can be bolstered through chest presses. There is no actual muscle in breasts; just milk-producing glands and fat.

Menstrual fluid is made up mostly of water.

The female brain is capable of distinguishing whether or not a man is attracted to her simply by the smell of his sweat, a study from Rice University has found.

Pregnancy may cause carpal tunnel syndrome in some pregnant women. The phenomenon is caused by edema, swelling caused by the extra fluids that accumulate in the body during pregnancy.

The female body contains less water than the male body. This is because fat tissue has a lower percentage of water, and females tend to have more fat.

Up until 8 weeks, all developing brains are female. After that, hormonal changes instigate physiological changes that lead to male anatomy.

Women have one-tenth the amount of testosterone as men.

Here’s an excuse to hug it out: Oxytocin, the so-called love hormone, is released whenever you touch a loved one. Oxytocin has been linked to lower blood pressure.

About 6,000 women a day reach menopause, according to statistics from American Congress of Obstetricians and Gynecologists.

Female humans differ from the rest of the animal kingdom in that they are capable of successfully reproducing year round; unlike most mammals, fertility is not restricted to brief periods of heat.

If you’re trying to get pregnant, you might want to say no to margaritas at happy hour. Extrapolating findings from an animal study, scientists concluded that lime juice may have anti-fertility properties.